Subject: [PATCH bpf-next v3 2/3] bpf: split cgroup_bpf_enabled per attach type

From: Stanislav Fomichev <[email-masked]>
Date: Tue, 5 Jan 2021 13:43:49 -0800

When we attach any cgroup hook, the rest (even if unused/unattached) start
to contribute small overhead. In particular, the one we want to avoid is
__cgroup_bpf_run_filter_skb which does two redirections to get to
the cgroup and pushes/pulls skb.

Let's split cgroup_bpf_enabled to be per-attach to make sure
only used attach types trigger.

I've dropped some existing high-level cgroup_bpf_enabled in some
places because BPF_PROG_CGROUP_XXX_RUN macros usually have another
cgroup_bpf_enabled check.

I also had to copy-paste BPF_CGROUP_RUN_SA_PROG_LOCK for
GETPEERNAME/GETSOCKNAME because type for cgroup_bpf_enabled[type]
has to be constant and known at compile time.

Signed-off-by: Stanislav Fomichev <[email-masked]>
Acked-by: Song Liu <[email-masked]>
---
 include/linux/bpf-cgroup.h | 36 +++++++++++++++++++-----------------
 kernel/bpf/cgroup.c        | 14 ++++++--------
 net/ipv4/af_inet.c         |  9 +++++----
 net/ipv4/udp.c             |  7 +++----
 net/ipv6/af_inet6.c        |  9 +++++----
 net/ipv6/udp.c             |  7 +++----
 6 files changed, 41 insertions(+), 41 deletions(-)

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index 72e69a0e1e8c..dd4b8e300746 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -23,8 +23,8 @@ struct ctl_table_header;
 
 #ifdef CONFIG_CGROUP_BPF
 
-extern struct static_key_false cgroup_bpf_enabled_key;
-#define cgroup_bpf_enabled static_branch_unlikely(&cgroup_bpf_enabled_key)
+extern struct static_key_false cgroup_bpf_enabled_key[MAX_BPF_ATTACH_TYPE];
+#define cgroup_bpf_enabled(type) static_branch_unlikely(&cgroup_bpf_enabled_key[type])
 
 DECLARE_PER_CPU(struct bpf_cgroup_storage*,
 		bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
@@ -185,7 +185,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk, skb)			      \
 ({									      \
 	int __ret = 0;							      \
-	if (cgroup_bpf_enabled)						      \
+	if (cgroup_bpf_enabled(BPF_CGROUP_INET_INGRESS))		      \
 		__ret = __cgroup_bpf_run_filter_skb(sk, skb,		      \
 						    BPF_CGROUP_INET_INGRESS); \
 									      \
@@ -195,7 +195,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb)			       \
 ({									       \
 	int __ret = 0;							       \
-	if (cgroup_bpf_enabled && sk && sk == skb->sk) {		       \
+	if (cgroup_bpf_enabled(BPF_CGROUP_INET_EGRESS) && sk && sk == skb->sk) { \
 		typeof(sk) __sk = sk_to_full_sk(sk);			       \
 		if (sk_fullsock(__sk))					       \
 			__ret = __cgroup_bpf_run_filter_skb(__sk, skb,	       \
@@ -207,7 +207,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_SK_PROG(sk, type)				       \
 ({									       \
 	int __ret = 0;							       \
-	if (cgroup_bpf_enabled) {					       \
+	if (cgroup_bpf_enabled(type)) {					       \
 		__ret = __cgroup_bpf_run_filter_sk(sk, type);		       \
 	}								       \
 	__ret;								       \
@@ -228,7 +228,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, type)				       \
 ({									       \
 	int __ret = 0;							       \
-	if (cgroup_bpf_enabled)						       \
+	if (cgroup_bpf_enabled(type))					       \
 		__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, type,     \
 							  NULL);	       \
 	__ret;								       \
@@ -237,7 +237,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, type, t_ctx)		       \
 ({									       \
 	int __ret = 0;							       \
-	if (cgroup_bpf_enabled)	{					       \
+	if (cgroup_bpf_enabled(type))	{				       \
 		lock_sock(sk);						       \
 		__ret = __cgroup_bpf_run_filter_sock_addr(sk, uaddr, type,     \
 							  t_ctx);	       \
@@ -252,8 +252,10 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_PROG_INET6_BIND_LOCK(sk, uaddr)			       \
 	BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, BPF_CGROUP_INET6_BIND, NULL)
 
-#define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (cgroup_bpf_enabled && \
-					    sk->sk_prot->pre_connect)
+#define BPF_CGROUP_PRE_CONNECT_ENABLED(sk)				       \
+	((cgroup_bpf_enabled(BPF_CGROUP_INET4_CONNECT) ||		       \
+	  cgroup_bpf_enabled(BPF_CGROUP_INET6_CONNECT)) &&		       \
+	 (sk)->sk_prot->pre_connect)
 
 #define BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr)			       \
 	BPF_CGROUP_RUN_SA_PROG(sk, uaddr, BPF_CGROUP_INET4_CONNECT)
@@ -297,7 +299,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_PROG_SOCK_OPS_SK(sock_ops, sk)			\
 ({									\
 	int __ret = 0;							\
-	if (cgroup_bpf_enabled)						\
+	if (cgroup_bpf_enabled(BPF_CGROUP_SOCK_OPS))			\
 		__ret = __cgroup_bpf_run_filter_sock_ops(sk,		\
 							 sock_ops,	\
 							 BPF_CGROUP_SOCK_OPS); \
@@ -307,7 +309,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops)				       \
 ({									       \
 	int __ret = 0;							       \
-	if (cgroup_bpf_enabled && (sock_ops)->sk) {	       \
+	if (cgroup_bpf_enabled(BPF_CGROUP_SOCK_OPS) && (sock_ops)->sk) {       \
 		typeof(sk) __sk = sk_to_full_sk((sock_ops)->sk);	       \
 		if (__sk && sk_fullsock(__sk))				       \
 			__ret = __cgroup_bpf_run_filter_sock_ops(__sk,	       \
@@ -320,7 +322,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type, major, minor, access)	      \
 ({									      \
 	int __ret = 0;							      \
-	if (cgroup_bpf_enabled)						      \
+	if (cgroup_bpf_enabled(BPF_CGROUP_DEVICE))			      \
 		__ret = __cgroup_bpf_check_dev_permission(type, major, minor, \
 							  access,	      \
 							  BPF_CGROUP_DEVICE); \
@@ -332,7 +334,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_RUN_PROG_SYSCTL(head, table, write, buf, count, pos)  \
 ({									       \
 	int __ret = 0;							       \
-	if (cgroup_bpf_enabled)						       \
+	if (cgroup_bpf_enabled(BPF_CGROUP_SYSCTL))			       \
 		__ret = __cgroup_bpf_run_filter_sysctl(head, table, write,     \
 						       buf, count, pos,        \
 						       BPF_CGROUP_SYSCTL);     \
@@ -343,7 +345,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 				       kernel_optval)			       \
 ({									       \
 	int __ret = 0;							       \
-	if (cgroup_bpf_enabled)						       \
+	if (cgroup_bpf_enabled(BPF_CGROUP_SETSOCKOPT))			       \
 		__ret = __cgroup_bpf_run_filter_setsockopt(sock, level,	       \
 							   optname, optval,    \
 							   optlen,	       \
@@ -354,7 +356,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 #define BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen)			       \
 ({									       \
 	int __ret = 0;							       \
-	if (cgroup_bpf_enabled)						       \
+	if (cgroup_bpf_enabled(BPF_CGROUP_GETSOCKOPT))			       \
 		get_user(__ret, optlen);				       \
 	__ret;								       \
 })
@@ -363,7 +365,7 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key,
 				       max_optlen, retval)		       \
 ({									       \
 	int __ret = retval;						       \
-	if (cgroup_bpf_enabled)						       \
+	if (cgroup_bpf_enabled(BPF_CGROUP_GETSOCKOPT))			       \
 		__ret = __cgroup_bpf_run_filter_getsockopt(sock, level,	       \
 							   optname, optval,    \
 							   optlen, max_optlen, \
@@ -427,7 +429,7 @@ static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map,
 	return 0;
 }
 
-#define cgroup_bpf_enabled (0)
+#define cgroup_bpf_enabled(type) (0)
 #define BPF_CGROUP_RUN_SA_PROG_LOCK(sk, uaddr, type, t_ctx) ({ 0; })
 #define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (0)
 #define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; })
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index ca6fa599a25d..adbecdcaa370 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -20,7 +20,7 @@
 
 #include "../cgroup/cgroup-internal.h"
 
-DEFINE_STATIC_KEY_FALSE(cgroup_bpf_enabled_key);
+DEFINE_STATIC_KEY_ARRAY_FALSE(cgroup_bpf_enabled_key, MAX_BPF_ATTACH_TYPE);
 EXPORT_SYMBOL(cgroup_bpf_enabled_key);
 
 void cgroup_bpf_offline(struct cgroup *cgrp)
@@ -129,7 +129,7 @@ static void cgroup_bpf_release(struct work_struct *work)
 			if (pl->link)
 				bpf_cgroup_link_auto_detach(pl->link);
 			kfree(pl);
-			static_branch_dec(&cgroup_bpf_enabled_key);
+			static_branch_dec(&cgroup_bpf_enabled_key[type]);
 		}
 		old_array = rcu_dereference_protected(
 				cgrp->bpf.effective[type],
@@ -500,7 +500,7 @@ int __cgroup_bpf_attach(struct cgroup *cgrp,
 	if (old_prog)
 		bpf_prog_put(old_prog);
 	else
-		static_branch_inc(&cgroup_bpf_enabled_key);
+		static_branch_inc(&cgroup_bpf_enabled_key[type]);
 	bpf_cgroup_storages_link(new_storage, cgrp, type);
 	return 0;
 
@@ -699,7 +699,7 @@ int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
 		cgrp->bpf.flags[type] = 0;
 	if (old_prog)
 		bpf_prog_put(old_prog);
-	static_branch_dec(&cgroup_bpf_enabled_key);
+	static_branch_dec(&cgroup_bpf_enabled_key[type]);
 	return 0;
 
 cleanup:
@@ -1364,8 +1364,7 @@ int __cgroup_bpf_run_filter_setsockopt(struct sock *sk, int *level,
 	 * attached to the hook so we don't waste time allocating
 	 * memory and locking the socket.
 	 */
-	if (!cgroup_bpf_enabled ||
-	    __cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_SETSOCKOPT))
+	if (__cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_SETSOCKOPT))
 		return 0;
 
 	/* Allocate a bit more than the initial user buffer for
@@ -1459,8 +1458,7 @@ int __cgroup_bpf_run_filter_getsockopt(struct sock *sk, int level,
 	 * attached to the hook so we don't waste time allocating
 	 * memory and locking the socket.
 	 */
-	if (!cgroup_bpf_enabled ||
-	    __cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_GETSOCKOPT))
+	if (__cgroup_bpf_prog_array_is_empty(cgrp, BPF_CGROUP_GETSOCKOPT))
 		return retval;
 
 	ctx.optlen = max_optlen;
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index b94fa8eb831b..6ba2930ff49b 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -777,18 +777,19 @@ int inet_getname(struct socket *sock, struct sockaddr *uaddr,
 			return -ENOTCONN;
 		sin->sin_port = inet->inet_dport;
 		sin->sin_addr.s_addr = inet->inet_daddr;
+		BPF_CGROUP_RUN_SA_PROG_LOCK(sk, (struct sockaddr *)sin,
+					    BPF_CGROUP_INET4_GETPEERNAME,
+					    NULL);
 	} else {
 		__be32 addr = inet->inet_rcv_saddr;
 		if (!addr)
 			addr = inet->inet_saddr;
 		sin->sin_port = inet->inet_sport;
 		sin->sin_addr.s_addr = addr;
-	}
-	if (cgroup_bpf_enabled)
 		BPF_CGROUP_RUN_SA_PROG_LOCK(sk, (struct sockaddr *)sin,
-					    peer ? BPF_CGROUP_INET4_GETPEERNAME :
-						   BPF_CGROUP_INET4_GETSOCKNAME,
+					    BPF_CGROUP_INET4_GETSOCKNAME,
 					    NULL);
+	}
 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 	return sizeof(*sin);
 }
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index dece195f212c..fc3c2e75e400 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1124,7 +1124,7 @@ int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		rcu_read_unlock();
 	}
 
-	if (cgroup_bpf_enabled && !connected) {
+	if (cgroup_bpf_enabled(BPF_CGROUP_UDP4_SENDMSG) && !connected) {
 		err = BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk,
 					    (struct sockaddr *)usin, &ipc.addr);
 		if (err)
@@ -1858,9 +1858,8 @@ int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
 		*addr_len = sizeof(*sin);
 
-		if (cgroup_bpf_enabled)
-			BPF_CGROUP_RUN_PROG_UDP4_RECVMSG_LOCK(sk,
-							(struct sockaddr *)sin);
+		BPF_CGROUP_RUN_PROG_UDP4_RECVMSG_LOCK(sk,
+						      (struct sockaddr *)sin);
 	}
 
 	if (udp_sk(sk)->gro_enabled)
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index a7e3d170af51..fc985658dc91 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -527,18 +527,19 @@ int inet6_getname(struct socket *sock, struct sockaddr *uaddr,
 		sin->sin6_addr = sk->sk_v6_daddr;
 		if (np->sndflow)
 			sin->sin6_flowinfo = np->flow_label;
+		BPF_CGROUP_RUN_SA_PROG_LOCK(sk, (struct sockaddr *)sin,
+					    BPF_CGROUP_INET6_GETPEERNAME,
+					    NULL);
 	} else {
 		if (ipv6_addr_any(&sk->sk_v6_rcv_saddr))
 			sin->sin6_addr = np->saddr;
 		else
 			sin->sin6_addr = sk->sk_v6_rcv_saddr;
 		sin->sin6_port = inet->inet_sport;
-	}
-	if (cgroup_bpf_enabled)
 		BPF_CGROUP_RUN_SA_PROG_LOCK(sk, (struct sockaddr *)sin,
-					    peer ? BPF_CGROUP_INET6_GETPEERNAME :
-						   BPF_CGROUP_INET6_GETSOCKNAME,
+					    BPF_CGROUP_INET6_GETSOCKNAME,
 					    NULL);
+	}
 	sin->sin6_scope_id = ipv6_iface_scope_id(&sin->sin6_addr,
 						 sk->sk_bound_dev_if);
 	return sizeof(*sin);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 9008f5796ad4..50611bd63647 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -409,9 +409,8 @@ int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 		}
 		*addr_len = sizeof(*sin6);
 
-		if (cgroup_bpf_enabled)
-			BPF_CGROUP_RUN_PROG_UDP6_RECVMSG_LOCK(sk,
-						(struct sockaddr *)sin6);
+		BPF_CGROUP_RUN_PROG_UDP6_RECVMSG_LOCK(sk,
+						      (struct sockaddr *)sin6);
 	}
 
 	if (udp_sk(sk)->gro_enabled)
@@ -1462,7 +1461,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 		fl6.saddr = np->saddr;
 	fl6.fl6_sport = inet->inet_sport;
 
-	if (cgroup_bpf_enabled && !connected) {
+	if (cgroup_bpf_enabled(BPF_CGROUP_UDP6_SENDMSG) && !connected) {
 		err = BPF_CGROUP_RUN_PROG_UDP6_SENDMSG_LOCK(sk,
 					   (struct sockaddr *)sin6, &fl6.saddr);
 		if (err)
-- 
2.29.2.729.g45daf8777d-goog